The present invention relates to network interfacing, and more particularly to a novel network transceiver having a Light Emitting Diode (LED) interface operable in parallel and serial modes in accordance with user requirements.
A Local Area Network (LAN) is a communication system that provides a connection among a number of independent computing stations within a small area, such as a single building or group of adjacent buildings. One type of network structure uses one or more repeaters in a star topology, with each repeater having several ports. A data packet received at one port is retransmitted to all other ports of the repeater. Each repeater in turn restores timing and amplitude degradation of data packets received at one port and retransmits the packets to all other ports.
Traditional Ethernet networks (10 BASE-T) operate at 10 Mb/s Ethernet protocol, as described by IEEE Standard 802.3, the majority of Ethernet interfaces currently operate at this data rate. However, a newer Ethernet standard, under IEEE standard 802.3 u, accomplishes the faster operation of 100 BASE-T systems, at a 100 Mb/s data rate (i.e., a 125 Mb/s encoded bit rate) using unshielded twisted pair (UTP) physical media. The 100 BASE-T standard defines operation over two pairs of category 5 UTP (100 BASE-TX) or category 3 UTP. The 100 BASE-FX network medium, covered by the 100 BASE-T standard, allows operation over dual fiber optic cabling.
Ethernet protocol provides for a Media Access Control (MAC), enabling network interface devices at each network node to share accesses to the network medium. One type of connection, termed a Media Independent Interface, or MII, connects the MAC to a physical layer (PHY) transceiver configured for a particular network medium, e.g., 10 BASE-T, 100 BASE-FX, or 100 BASE-TX. The physical layer transceiver is configured for converting the MII protocol signals output by the MAC into analog network signals, such as Multiple Layer Transition-3 (MLT-3) signals for 100 Mb/s Ethernet networks, or Manchester-encoded signals for 10 Mb/s Ethernet networks.
The transceiver may be provided with a Light Emitting Diode (LED) interface for connecting to LEDs that indicate network status and events, such as link status, collision status, receive and transmit activity, etc. However, for some transceiver applications, users need to continuously monitor LED information on multiple aspects of network activities, whereas other transceiver applications require only basic status information.
Therefore, it would be desirable to provide the transceiver with ability to configure the LED interface so as to support various LED modes depending on user requirements.
The invention provides a novel network transceiver having multiple ports for supporting data communications with multiple data communication devices in a local area network, such as one conforming to Ethernet protocol. The transceiver comprises an indication interface having at least a pin per port for providing connection to indication devices, such as LEDs. An indication interface configuration circuit configures the indication interface to operate in a parallel indication mode to provide parallel output of status data for the multiple physical ports, or in a serial indication mode, in which status data for the multiple physical ports is being outputted sequentially in a serial data stream.
In accordance with one aspect of the invention, the physical ports support data communication at first and second data rates. In the parallel indication mode, the indication interface comprises a first pin for each port to indicate status of data communication at the first data rate, and a second pin for each port to indicate status of data communication at the second data rate.
In the serial indication mode, the indication interface may be configured to have a data pin, a frame pin and a clock pin. The data pin is provided for shifting out a serial status data stream composed of status bits representing statuses of data communication via the multiple physical ports. The serial status data stream comprises multiple frames, each of which indicates a plurality of events representing the multiple physical ports at a given time period. The frame pin is used for transferring a frame signal that indicates the boundary between the frames. The clock pin transfers a clock signal that synchronizes the transfer of the serial status data stream.
Preferably, the indication interface configuration circuit is programmable to configure the indication interface in the parallel mode in response to a first control signal, and to configure the indication interface in the serial mode in response to a second control signal.
In accordance with another aspect of the invention, in the parallel indication mode, the indication interface presents a single event at a time for each port; and in the serial mode, the indication interface presents a plurality of various events for each port sequentially in a serial data stream.
Various objects and features of the present invention will become more readily apparent to those skilled in the art from the following description of a specific embodiment thereof, especially when taken in conjunction with the accompanying drawings.